Enhanced internet protocol multimedia subsystem call handling

ABSTRACT

Systems and methods of enabling access for non-emergency voice calls are described. A UE operates in a network supporting voice services via a multitude of RATs. The UE attempts to access the network via a first RAT offering voice services and data services. If the UE does not receive a response from the network within a first time period, the UE re-attempts the access to the network via the first RAT. If the number of access attempts for which the UE does not receive a response is at least a threshold value, the UE refrains during a second time period from further access attempts via the first RAT for the purpose of receiving data services, and continues to attempt access via the first or second RAT for the purpose of receiving voice services.

PRIORITY CLAIM

This application is a U.S. National Stage Filing under 35 U.S.C. 371from International Application No. PCT/US2018/058958, filed Nov. 2, 2018and published in English as WO 2019/099212 on May 23, 2019, which claimsthe benefit of priority to U.S. Provisional Patent Application Ser. No.62/587,649, filed Nov. 17, 2017, each of which is incorporated herein byreference in its entirety.

TECHNICAL FIELD

Embodiments pertain to radio access networks (RANs). Some embodimentsrelate to cellular and wireless local area network (WLAN) networks,including Third Generation Partnership Project Long Term Evolution (3GPPLTE) networks and LTE advanced (LTE-A) networks as well as legacynetworks, 4^(th) generation (4G) networks and 5^(th) generation (5G)networks. Some embodiments relate to non-emergency access incommunication networks.

BACKGROUND

The use of various types of systems has increased due to both anincrease in the types of devices user equipment (UEs) using networkresources as well as the amount of data and bandwidth being used byvarious applications, such as video streaming, operating on these UEs.To increase the ability of the network to contend with the explosion innetwork use and variation, the next generation of communication systemsis being created. While the advent of any new technology, especially theintroduction of a complex new communication system engenders a largeamount of problems both in the system itself and in compatibility withprevious systems and devices, issues continue to abound in existingsystems. For example, issues still exist with access to the network fornon-emergency services in the existing 3G and 4G system, which, if notcorrected, may continue to be problematic in 5G systems.

BRIEF DESCRIPTION OF THE FIGURES

In the figures, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The figures illustrate generally, by way of example, but notby way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 illustrates a UE in accordance with some embodiments.

FIG. 2 illustrates a base station or infrastructure equipment radio headin accordance with some embodiments.

FIG. 3 illustrates millimeter wave communication circuitry in accordancewith some embodiments.

FIG. 4 is an illustration of protocol functions in accordance with someembodiments.

FIG. 5 is an illustration of protocol entities in accordance with someembodiments.

FIG. 6 illustrates an architecture of a system of a network inaccordance with some embodiments.

FIG. 7 illustrates a service request procedure in accordance with someembodiments.

FIG. 8 illustrates a service request procedure in accordance with someembodiments.

FIG. 9 illustrates a service request procedure in accordance with someembodiments.

FIG. 10 illustrates a flowchart of a service request procedure inaccordance with some embodiments.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustratespecific embodiments to enable those skilled in the art to practicethem. Other embodiments may incorporate structural, logical, electrical,process, and other changes. Portions and features of some embodimentsmay be included in, or substituted for, those of other embodiments.Embodiments set forth in the claims encompass all available equivalentsof those claims.

Any of the radio access technologies (RATs) described herein may operateaccording to any one or more of the following exemplary radiocommunication technologies and/or standards including, but not limitedto: a Global System for Mobile Communications (GSM) radio communicationtechnology, a General Packet Radio Service (GPRS) radio communicationtechnology, an Enhanced Data Rates for GSM Evolution (EDGE) radiocommunication technology, and/or a Third Generation Partnership Project(3GPP) radio communication technology, for example Universal MobileTelecommunications System (UMTS), Freedom of Multimedia Access (FOMA),3GPP Long Term Evolution (LTE), 3GPP Long Term Evolution Advanced (LTEAdvanced), Code division multiple access 2000 (CDMA2000), CellularDigital Packet Data (CDPD), Mobitex, Third Generation (3G), CircuitSwitched Data (CSD), High-Speed Circuit-Switched Data (HSCSD), UniversalMobile Telecommunications System (Third Generation) (UMTS (3G)),Wideband Code Division Multiple Access (Universal MobileTelecommunications System) (W-CDMA (UMTS)), High Speed Packet Access(HSPA), High-Speed Downlink Packet Access (HSDPA), High-Speed UplinkPacket Access (HSUPA), High Speed Packet Access Plus (HSPA+), UniversalMobile Telecommunications System-Time-Division Duplex (UMTS-TDD), TimeDivision-Code Division Multiple Access (TD-CDMA), TimeDivision-Synchronous Code Division Multiple Access (TD-CDMA), 3rdGeneration Partnership Project Release 8 (Pre-4th Generation) (3GPP Rel.8 (Pre-4G)), 3GPP Rel. 9 (3rd Generation Partnership Project Release 9),3GPP Rel. 10 (3rd Generation Partnership Project Release 10), 3GPP Rel.11 (3rd Generation Partnership Project Release 11), 3GPP Rel. 12 (3rdGeneration Partnership Project Release 12), 3GPP Rel. 13 (3rd GenerationPartnership Project Release 13), 3GPP Rel. 14 (3rd GenerationPartnership Project Release 14), 3GPP Rel. 15 (3rd GenerationPartnership Project Release 15), 3GPP Rel. 16 (3rd GenerationPartnership Project Release 16), 3GPP Rel. 17 (3rd GenerationPartnership Project Release 17), 3GPP Rel. 18 (3rd GenerationPartnership Project Release 18), 3GPP 5G, (3GPP NR), 3GPP LTE Extra,LTE-Advanced Pro, LTE Licensed-Assisted Access (LAA), MulteFire, UMTSTerrestrial Radio Access (UTRA), Evolved UMTS Terrestrial Radio Access(E-UTRA), Long Term Evolution Advanced (4th Generation) (LTE Advanced(4G)), cdmaOne (2G), Code division multiple access 2000 (Thirdgeneration) (CDMA2000 (3G)), Evolution-Data Optimized or Evolution-DataOnly (EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)),Total Access Communication System/Extended Total Access CommunicationSystem (TACS/ETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)),Push-to-talk (PIT), Mobile Telephone System (MTS), Improved MobileTelephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT(Norwegian for Offentlig Landmobil Telefoni, Public Land MobileTelephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, orMobile telephony system D), Public Automated Land Mobile (Autotel/PALM),ARP (Finnish for Autoradiopuhelin, “car radio phone”), NMT (NordicMobile Telephony), High capacity version of NTT (Nippon Telegraph andTelephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex,DataTAC, Integrated Digital Enhanced Network (iDEN), Personal DigitalCellular (PDC), Circuit Switched Data (CSD), Personal Handy-phone System(PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst,Unlicensed Mobile Access (UMA), also referred to as also referred to as3GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth®,Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general(wireless systems operating at 10-300 GHz and above such as WiGig, IEEE802.1 lad, IEEE 802.1 lay, and the like), technologies operating above300 GHz and THz bands, (3GPP/LTE based or IEEE 802.11p and other),Vehicle-to-Vehicle (V2V), Vehicle-to-X (V2X), Vehicle-to-Infrastructure(V2I), and Infrastructure-to-Vehicle (12V) communication technologies,3GPP cellular V2X, DSRC (Dedicated Short Range Communications)communication systems such as Intelligent-Transport-Systems and others.

Aspects described herein can be used in the context of any spectrummanagement scheme including, for example, dedicated licensed spectrum,unlicensed spectrum, (licensed) shared spectrum (such as Licensed SharedAccess (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and furtherfrequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and furtherfrequencies). Applicable exemplary spectrum bands include IMT(International Mobile Telecommunications) spectrum (including 450-470MHz, 790-960 MHz, 1710-2025 MHz, 2110-2200 MHz, 2300-2400 MHz, 2500-2690MHz, 698-790 MHz, 610-790 MHz, 3400-3600 MHz, to name a few),IMT-advanced spectrum, IMT-2020 spectrum (expected to include 3600-3800MHz, 3.5 GHz bands, 700 MHz bands, bands within the 24.25-86 GHz range,for example), spectrum made available under the Federal CommunicationsCommission's “Spectrum Frontier” 5G initiative (including 27.5-28.35GHz, 29.1-29.25 GHz, 31-31.3 GHz, 37-38.6 GHz, 38.6-40 GHz, 42-42.5 GHz,57-64 GHz, 71-76 GHz, 81-86 GHz and 92-94 GHz, etc), the ITS(Intelligent Transport Systems) band of 5.9 GHz (typically 5.85-5.925GHz) and 63-64 GHz, bands currently allocated to WiGig such as WiGigBand 1 (57.24-59.40 GHz), WiGig Band 2 (59.40-61.56 GHz), WiGig Band 3(61.56-63.72 GHz), and WiGig Band 4 (63.72-65.88 GHz); the 70.2 GHz-71GHz band; any band between 65.88 GHz and 71 GHz; bands currentlyallocated to automotive radar applications such as 76-81 GHz; and futurebands including 94-300 GHz and above. Furthermore, the scheme can beused on a secondary basis on bands such as the TV White Space bands(typically below 790 MHz) where in particular the 400 MHz and 700 MHzbands can be employed. Besides cellular applications, specificapplications for vertical markets may be addressed, such as PMSE(Program Making and Special Events), medical, health, surgery,automotive, low-latency, drones, and the like.

Aspects described herein can also be applied to different Single Carrieror OFDM flavors (CP-OFDM, SC-FDMA, SC-OFDM, filter bank-basedmulticarrier (FBMC), OFDMA, etc.) and in particular 3GPP NR (New Radio)by allocating the OFDM carrier data bit vectors to the correspondingsymbol resources.

FIG. 1 illustrates a UE in accordance with some embodiments. The userdevice 100 may be a mobile device in some aspects and includes anapplication processor 105, baseband processor 110 (also referred to as abaseband sub-system), radio front end module (RFEM) 115, memory 120,connectivity sub-system 125, near field communication (NFC) controller130, audio driver 135, camera driver 140, touch screen 145, displaydriver 150, sensors 155, removable memory 160, power managementintegrated circuit (PMIC) 165 and smart battery 170.

In some aspects, application processor 105 may include, for example, oneor more CPU cores and one or more of cache memory, low drop-out voltageregulators (LDOs), interrupt controllers, serial interfaces such asserial peripheral interface (SPI), inter-integrated circuit (I²C) oruniversal programmable serial interface circuit, real time clock (RTC),timer-counters including interval and watchdog timers, general purposeinput-output (IO), memory card controllers such as securedigital/multi-media card (SD/MMC) or similar, universal serial bus (USB)interfaces, mobile industry processor interface (MIPI) interfaces andJoint Test Access Group (JTAG) test access ports.

In some aspects, baseband processor 110 may be implemented, for example,as a solder-down substrate including one or more integrated circuits, asingle packaged integrated circuit soldered to a main circuit board,and/or a multi-chip module containing two or more integrated circuits.

FIG. 2 illustrates a base station in accordance with some embodiments.The base station radio head 200 may include one or more of applicationprocessor 205, baseband processor 210, one or more radio front endmodules 215, memory 220, power management circuitry 225, power teecircuitry 230, network controller 235, network interface connector 240,satellite navigation receiver 245, and user interface 250.

In some aspects, application processor 205 may include one or more CPUcores and one or more of cache memory, low drop-out voltage regulators(LDOs), interrupt controllers, serial interfaces such as SPI, I²C oruniversal programmable serial interface, real time clock (RTC),timer-counters including interval and watchdog timers, general purposeIO, memory card controllers such as SD/MMC or similar, USB interfaces,MIPI interfaces and Joint Test Access Group (JTAG) test access ports.

In some aspects, baseband processor 210 may be implemented, for example,as a solder-down substrate including one or more integrated circuits, asingle packaged integrated circuit soldered to a main circuit board or amulti-chip module containing two or more integrated circuits.

In some aspects, memory 220 may include one or more of volatile memoryincluding dynamic random access memory (DRAM) and/or synchronous dynamicrandom access memory (SDRAM), and nonvolatile memory (NVM) includinghigh-speed electrically erasable memory (commonly referred to as Flashmemory), phase change random access memory (PRAM), magnetoresistiverandom access memory (MRAM) and/or a three-dimensional crosspointmemory. Memory 220 may be implemented as one or more of solder downpackaged integrated circuits, socketed memory modules and plug-in memorycards.

In some aspects, power management integrated circuitry 225 may includeone or more of voltage regulators, surge protectors, power alarmdetection circuitry and one or more backup power sources such as abattery or capacitor. Power alarm detection circuitry may detect one ormore of brown out (under-voltage) and surge (over-voltage) conditions.

In some aspects, power tee circuitry 230 may provide for electricalpower drawn from a network cable to provide both power supply and dataconnectivity to the base station radio head 200 using a single cable.

In some aspects, network controller 235 may provide connectivity to anetwork using a standard network interface protocol such as Ethernet.Network connectivity may be provided using a physical connection whichis one of electrical (commonly referred to as copper interconnect),optical or wireless.

In some aspects, satellite navigation receiver 245 may include circuitryto receive and decode signals transmitted by one or more navigationsatellite constellations such as the global positioning system (GPS),Globalnaya Navigatsionnaya Sputnikovaya Sistema (GLONASS), Galileoand/or BeiDou. The receiver 245 may provide data to applicationprocessor 205 which may include one or more of position data or timedata. Application processor 205 may use time data to synchronizeoperations with other radio base stations.

In some aspects, user interface 250 may include one or more of physicalor virtual buttons, such as a reset button, one or more indicators suchas light emitting diodes (LEDs) and a display screen.

A radio front end module may incorporate a millimeter wave radio frontend module (RFEM) and one or more sub-millimeter wave radio frequencyintegrated circuits (RFIC). In this aspect, the one or moresub-millimeter wave RFICs may be physically separated from a millimeterwave RFEM. The RFICs may include connection to one or more antennas. TheRFEM may be connected to multiple antennas. Alternatively bothmillimeter wave and sub-millimeter wave radio functions may beimplemented in the same physical radio front end module. Thus, the RFEMmay incorporate both millimeter wave antennas and sub-millimeter waveantennas.

FIG. 3 illustrates millimeter wave communication circuitry in accordancewith some embodiments. Circuitry 300 is alternatively grouped accordingto functions. Components as shown in 300 are shown here for illustrativepurposes and may include other components not shown here.

Millimeter wave communication circuitry 300 may include protocolprocessing circuitry 305, which may implement one or more of mediumaccess control (MAC), radio link control (RLC), packet data convergenceprotocol (PDCP), radio resource control (RRC) and non-access stratum(NAS) functions. Protocol processing circuitry 305 may include one ormore processing cores (not shown) to execute instructions and one ormore memory structures (not shown) to store program and datainformation.

Millimeter wave communication circuitry 300 may further include digitalbaseband circuitry 310, which may implement physical layer (PHY)functions including one or more of hybrid automatic repeat request(HARQ) functions, scrambling and/or descrambling, coding and/ordecoding, layer mapping and/or de-mapping, modulation symbol mapping,received symbol and/or bit metric determination, multi-antenna portpre-coding and/or decoding which may include one or more of space-time,space-frequency or spatial coding, reference signal generation and/ordetection, preamble sequence generation and/or decoding, synchronizationsequence generation and/or detection, control channel signal blinddecoding, and other related functions.

Millimeter wave communication circuitry 300 may further include transmitcircuitry 315, receive circuitry 320 and/or antenna array circuitry 330.

Millimeter wave communication circuitry 300 may further include radiofrequency (RF) circuitry 325. In an aspect, RF circuitry 325 may includemultiple parallel RF chains for one or more of transmit or receivefunctions, each connected to one or more antennas of the antenna array330.

In an aspect of the disclosure, protocol processing circuitry 305 mayinclude one or more instances of control circuitry (not shown) toprovide control functions for one or more of digital baseband circuitry310, transmit circuitry 315, receive circuitry 320, and/or radiofrequency circuitry 325.

The transmit circuitry of may include one or more of digital to analogconverters (DACs), analog baseband circuitry, up-conversion circuitryand filtering and amplification circuitry, the latter of which mayprovide an amount of amplification that is controlled by an automaticgain control (AGC). In another aspect, the transmit circuitry mayinclude digital transmit circuitry and output circuitry.

The radio frequency circuitry may include one or more instances of radiochain circuitry, which in some aspects may include one or more filters,power amplifiers, low noise amplifiers, programmable phase shifters andpower supplies. The radio frequency circuitry may include powercombining and dividing circuitry in some aspects. In some aspects, thepower combining and dividing circuitry may operate bidirectionally, suchthat the same physical circuitry may be configured to operate as a powerdivider when the device is transmitting, and as a power combiner whenthe device is receiving. In some aspects, the power combining anddividing circuitry may one or more include wholly or partially separatecircuitries to perform power dividing when the device is transmittingand power combining when the device is receiving. In some aspects, thepower combining and dividing circuitry may include passive circuitrycomprising one or more two-way power divider/combiners arranged in atree. In some aspects, the power combining and dividing circuitry mayinclude active circuitry comprising amplifier circuits.

In some aspects, the radio frequency circuitry may connect to transmitcircuitry and receive circuitry via one or more radio chain interfacesor a combined radio chain interface. In some aspects, one or more radiochain interfaces may provide one or more interfaces to one or morereceive or transmit signals, each associated with a single antennastructure which may comprise one or more antennas.

In some aspects, the combined radio chain interface may provide a singleinterface to one or more receive or transmit signals, each associatedwith a group of antenna structures comprising one or more antennas.

The receive circuitry may include one or more of parallel receivecircuitry and/or one or more of combined receive circuitry. In someaspects, the one or more parallel receive circuitry and one or morecombined receive circuitry may include one or more IntermediateFrequency (IF) down-conversion circuitry, IF processing circuitry,baseband down-conversion circuitry, baseband processing circuitry andanalog-to-digital converter (ADC) circuitry.

In an aspect, the RF circuitry may include one or more of each of IFinterface circuitry, filtering circuitry, up conversion and downconversion circuitry, synthesizer circuitry, filtering and amplificationcircuitry, power combining and dividing circuitry and radio chaincircuitry.

In an aspect, the baseband processor may contain one or more digitalbaseband systems. In an aspect, the one or more digital basebandsubsystems may be coupled via an interconnect subsystem to one or moreof a CPU subsystem, audio subsystem and interface subsystem. In anaspect, the one or more digital baseband subsystems may be coupled viaanother interconnect subsystem to one or more of each of digitalbaseband interface and mixed-signal baseband sub-system. In an aspect,the interconnect subsystems may each include one or more of each ofbuses point-to-point connections and network-on-chip (NOC) structures.

In an aspect, an audio sub-system may include one or more of digitalsignal processing circuitry, buffer memory, program memory, speechprocessing accelerator circuitry, data converter circuitry such asanalog-to-digital and digital-to-analog converter circuitry, and analogcircuitry including one or more of amplifiers and filters. In an aspect,a mixed signal baseband sub-system may include one or more of an IFinterface, analog IF subsystem, down converter and up convertersubsystem, analog baseband subsystem, data converter subsystem,synthesizer and control sub-system.

A baseband processing subsystem may include one or more of each of DSPsub-systems, interconnect sub-system, boot loader sub-system, sharedmemory sub-system, digital I/O sub-system, digital baseband interfacesub-system and audio sub-system. In an example aspect, the basebandprocessing subsystem may include one or more of each of an acceleratorsubsystem, buffer memory, interconnect sub-system, audio sub-system,shared memory sub-system, digital I/O subsystem, controller sub-systemand digital baseband interface sub-system.

In an aspect, the boot loader sub-system may include digital logiccircuitry configured to perform configuration of the program memory andrunning state associated with each of the one or more DSP sub-systems.The configuration of the program memory of each of the one or more DSPsub-systems may include loading executable program code from storageexternal to baseband processing sub-system. The configuration of therunning state associated with each of the one or more DSP sub-systemsmay include one or more of the steps of: setting the state of at leastone DSP core which may be incorporated into each of the one or more DSPsub-systems to a state in which it is not running, and setting the stateof at least one DSP core which may be incorporated into each of the oneor more DSP sub-systems into a state in which it begins executingprogram code starting from a predefined memory location.

In an aspect, the shared memory sub-system may include one or more of aread-only memory (ROM), static random access memory (SRAM), embeddeddynamic random access memory (eDRAM) and non-volatile random accessmemory (NVRAM). In an aspect, the digital I/O subsystem may include oneor more of serial interfaces such as I²C, SPI or other 1, 2 or 3-wireserial interfaces, parallel interfaces such as general-purposeinput-output (GPIO), register access interfaces and direct memory access(DMA). In an aspect, a register access interface implemented in digitalI/O subsystem may permit a microprocessor core external to basebandprocessing subsystem (1000 cross reference) to read and/or write one ormore of control and data registers and memory. In an aspect, DMA logiccircuitry implemented in digital I/O subsystem may permit transfer ofcontiguous blocks of data between memory locations including memorylocations internal and external to baseband processing subsystem. In anaspect, the digital baseband interface sub-system may provide for thetransfer of digital baseband samples between the baseband processingsubsystem and mixed signal baseband or radio-frequency circuitryexternal to the baseband processing subsystem. In an aspect, the digitalbaseband samples transferred by the digital baseband interfacesub-system may include in-phase and quadrature (I/Q) samples.

In an aspect, the controller sub-system may include one or more of eachof control and status registers and control state machines. In anaspect, the control and status registers may be accessed via a registerinterface and may provide for one or more of: starting and stoppingoperation of control state machines, resetting control state machines toa default state, configuring optional processing features, configuringthe generation of interrupts and reporting the status of operations. Inan aspect, each of the one or more control state machines may controlthe sequence of operation of each of the one or more acceleratorsub-systems.

In an aspect, the DSP sub-system may include one or more of each of aDSP core sub-system, local memory, direct memory access sub-system,accelerator sub-system, external interface sub-system, power managementunit and interconnect sub-system. In an aspect, the local memory mayinclude one or more of each of read-only memory, static random accessmemory or embedded dynamic random access memory. In an aspect, thedirect memory access sub-system may provide registers and control statemachine circuitry adapted to transfer blocks of data between memorylocations including memory locations internal and external to thedigital signal processor sub-system. In an aspect, the externalinterface sub-system may provide for access by a microprocessor systemexternal to DSP sub-system to one or more of memory, control registersand status registers which may be implemented in the DSP sub-system. Inan aspect, the external interface sub-system may provide for transfer ofdata between local memory and storage external to the DSP sub-systemunder the control of one or more of the DMA sub-system and DSP coresub-system.

FIG. 4 is an illustration of protocol functions in accordance with someembodiments. The protocol functions may be implemented in a wirelesscommunication device according to some aspects. In some aspects, theprotocol layers may include one or more of physical layer (PHY) 410,medium access control layer (MAC) 420, radio link control layer (RLC)430, packet data convergence protocol layer (PDCP) 440, service dataadaptation protocol (SDAP) layer 447, radio resource control layer (RRC)455, and non-access stratum (NAS) layer 457, in addition to other higherlayer functions not illustrated.

According to some aspects, the protocol layers may include one or moreservice access points that may provide communication between two or moreprotocol layers. According to some aspects, the PHY 410 may transmit andreceive physical layer signals 405 that may be received or transmittedrespectively by one or more other communication devices. According tosome aspects, physical layer signals 405 may comprise one or morephysical channels.

According to some aspects, an instance of PHY 410 may process requestsfrom and provide indications to an instance of MAC 420 via one or morephysical layer service access points (PHY-SAP) 415. According to someaspects, requests and indications communicated via PHY-SAP 415 maycomprise one or more transport channels.

According to some aspects, an instance of MAC 410 may process requestsfrom and provide indications to an instance of RLC 430 via one or moremedium access control service access points (MAC-SAP) 425. According tosome aspects, requests and indications communicated via MAC-SAP 425 maycomprise one or more logical channels.

According to some aspects, an instance of RLC 430 may process requestsfrom and provide indications to an instance of PDCP 440 via one or moreradio link control service access points (RLC-SAP) 435. According tosome aspects, requests and indications communicated via RLC-SAP 435 maycomprise one or more RLC channels.

According to some aspects, an instance of PDCP 440 may process requestsfrom and provide indications to one or more of an instance of RRC 455and one or more instances of SDAP 447 via one or more packet dataconvergence protocol service access points (PDCP-SAP) 445. According tosome aspects, requests and indications communicated via PDCP-SAP 445 maycomprise one or more radio bearers.

According to some aspects, an instance of SDAP 447 may process requestsfrom and provide indications to one or more higher layer protocolentities via one or more service data adaptation protocol service accesspoints (SDAP-SAP) 449. According to some aspects, requests andindications communicated via SDAP-SAP 449 may comprise one or morequality of service (QoS) flows.

According to some aspects, RRC entity 455 may configure, via one or moremanagement service access points (M-SAP), aspects of one or moreprotocol layers, which may include one or more instances of PHY 410, MAC420, RLC 430, PDCP 440 and SDAP 447. According to some aspects, aninstance of RRC 455 may process requests from and provide indications toone or more NAS entities via one or more RRC service access points(RRC-SAP) 456.

FIG. 5 is an illustration of protocol entities in accordance with someembodiments. The protocol entities may be implemented in wirelesscommunication devices, including one or more of a user equipment (UE)560, a base station, which may be termed an evolved node B (eNB), or newradio node B (gNB) 580, and a network function, which may be termed amobility management entity (MME), or an access and mobility managementfunction (AMF) 594, according to some aspects.

According to some aspects, gNB 580 may be implemented as one or more ofa dedicated physical device such as a macro-cell, a femto-cell or othersuitable device, or in an alternative aspect, may be implemented as oneor more software entities running on server computers as part of avirtual network termed a cloud radio access network (CRAN).

According to some aspects, one or more protocol entities that may beimplemented in one or more of UE 560, gNB 580 and AMF 594, may bedescribed as implementing all or part of a protocol stack in which thelayers are considered to be ordered from lowest to highest in the orderPHY, MAC, RLC, PDCP, RRC and NAS. According to some aspects, one or moreprotocol entities that may be implemented in one or more of UE 560, gNB580 and AMF 594, may communicate with a respective peer protocol entitythat may be implemented on another device, using the services ofrespective lower layer protocol entities to perform such communication.

According to some aspects, UE PHY 572 and peer entity gNB PHY 590 maycommunicate using signals transmitted and received via a wirelessmedium. According to some aspects, UE MAC 570 and peer entity gNB MAC588 may communicate using the services provided respectively by UE PHY572 and gNB PHY 590. According to some aspects, UE RLC 568 and peerentity gNB RLC 586 may communicate using the services providedrespectively by UE MAC 570 and gNB MAC 588. According to some aspects,UE PDCP 566 and peer entity gNB PDCP 584 may communicate using theservices provided respectively by UE RLC 568 and 5GNB RLC 586. Accordingto some aspects, UE RRC 564 and gNB RRC 582 may communicate using theservices provided respectively by UE PDCP 566 and gNB PDCP 584.According to some aspects, UE NAS 562 and AMF NAS 592 may communicateusing the services provided respectively by UE RRC 564 and gNB RRC 582.

The UE and gNB may communicate using a radio frame structure that has apredetermined duration and repeats in a periodic manner with arepetition interval equal to the predetermined duration. The radio framemay be divided into two or more subframes. In an aspect, subframes maybe of predetermined duration which may be unequal. In an alternativeaspect, subframes may be of a duration which is determined dynamicallyand varies between subsequent repetitions of the radio frame. In anaspect of frequency division duplexing (FDD), the downlink radio framestructure is transmitted by a base station to one or devices, and uplinkradio frame structure transmitted by a combination of one or moredevices to a base station. The radio frame may have a duration of 10 ms.The radio frame may be divided into slots each of duration 0.5 ms, andnumbered from 0 to 19. Additionally, each pair of adjacent slotsnumbered 2i and 2i+1, where i is an integer, may be referred to as asubframe. Each subframe may include a combination of one or more ofdownlink control information, downlink data information, uplink controlinformation and uplink data information. The combination of informationtypes and direction may be selected independently for each subframe.

According to some aspects, the downlink frame and uplink frame may havea duration of 10 ms, and uplink frame may be transmitted with a timingadvance with respect to downlink frame. According to some aspects, thedownlink frame and uplink frame may each be divided into two or moresubframes, which may be 1 ms in duration. According to some aspects,each subframe may consist of one or more slots. In some aspects, thetime intervals may be represented in units of T_(s). According to someaspects, T_(s) may be defined as 1/(30.720×1000) seconds. According tosome aspects, a radio frame may be defined as having duration30.720·T_(s), and a slot may be defined as having duration 15.360·T_(s).According to some aspects, T_(s) may be defined asT _(s)=1/(Δf _(max) ·N _(f)),

where Δf_(max)=480×10³ and Nf=4,096. According to some aspects E, thenumber of slots may be determined based on a numerology parameter, whichmay be related to a frequency spacing between subcarriers of amulticarrier signal used for transmission.

Constellation designs of a single carrier modulation scheme that may betransmitted or received may contain 2 points, known as binary phaseshift keying (BPSK), 4 points, known as quadrature phase shift keying(QPSK), 16 points, known as quadrature amplitude modulation (QAM) with16 points (16QAM or QAM 16) or higher order modulation constellations,containing for example 64, 256 or 1024 points. In the constellations,the binary codes are assigned to the points of the constellation using ascheme such that nearest-neighbor points, that is, pairs of pointsseparated from each other by the minimum Euclidian distance, have anassigned binary code differing by only one binary digit. For example,the point assigned code 1000 has nearest neighbor points assigned codes1001, 0000, 1100 and 1010, each of which differs from 1000 by only onebit.

Alternatively, the constellation points may be arranged in a squaregrid, and may be arranged such that there is an equal distance on thein-phase and quadrature plane between each pair of nearest-neighborconstellation points. In an aspect, the constellation points may bechosen such that there is a pre-determined maximum distance from theorigin of the in-phase and quadrature plane of any of the allowedconstellation points, the maximum distance represented by a circle. Inan aspect, the set of allowed constellation points may exclude thosethat would fall within square regions at the corners of a square grid.The constellation points are shown on orthogonal in-phase and quadratureaxes, representing, respectively, amplitudes of sinusoids at the carrierfrequency and separated in phase from one another by 90 degrees. In anaspect, the constellation points are grouped into two or more sets ofconstellation points, the points of each set being arranged to have anequal distance to the origin of the in-phase and quadrature plane, andlying on one of a set of circles centered on the origin.

To generate multicarrier baseband signals for transmission, data may beinput to an encoder to generate encoded data. The encoder may include acombination of one or more of error detecting, error correcting, ratematching, and interleaving. The encoder may further include a step ofscrambling. In an aspect, encoded data may be input to a modulationmapper to generate complex valued modulation symbols. The modulationmapper may map groups containing one or more binary digits, selectedfrom the encoded data, to complex valued modulation symbols according toone or more mapping tables. In an aspect, complex-valued modulationsymbols may be input to the layer mapper to be mapped to one or morelayer mapped modulation symbol streams. Representing a stream ofmodulation symbols 440 as d(i) where i represents a sequence numberindex, and the one or more streams of layer mapped symbols as x^((k))(i)where k represents a stream number index and i represents a sequencenumber index, the layer mapping function for a single layer may beexpressed as:x ⁽⁰⁾(i)=d(i)

and the layer mapping for two layers may be expressed as:x ⁽⁰⁾(i)=d(2i)x ⁽¹⁾(i)=d(2i+1)

Layer mapping may be similarly represented for more than two layers.

In an aspect, one or more streams of layer mapped symbols may be inputto the precoder which generates one or more streams of precoded symbols.Representing the one or more streams of layer mapped symbols as a blockof vectors:[x ⁽⁰⁾(i) . . . x ^((v-1))(i)]^(T)

where i represents a sequence number index in the range 0 to M_(symb)^(layer)−1 the output is represented as a block of vectors:[z ⁽⁰⁾(i) . . . z ^((P-1))(i)]^(T)

where i represents a sequence number index in the range 0 to M_(symb)^(ap)−1. The precoding operation may be configured to include one ofdirect mapping using a single antenna port, transmit diversity usingspace-time block coding, or spatial multiplexing.

In an aspect, each stream of precoded symbols may be input to a resourcemapper which generates a stream of resource mapped symbols. The resourcemapper may map precoded symbols to frequency domain subcarriers and timedomain symbols according to a mapping which may include contiguous blockmapping, randomized mapping or sparse mapping according to a mappingcode.

In an aspect, the resource mapped symbols may be input to multicarriergenerator which generates a time domain baseband symbol. Multicarriergenerator may generate time domain symbols using, for example, aninverse discrete Fourier transform (DFT), commonly implemented as aninverse fast Fourier transform (FFT) or a filter bank comprising one ormore filters. In an aspect, where resource mapped symbols 455 arerepresented as s_(k)(i), where k is a subcarrier index and i is a symbolnumber index, a time domain complex baseband symbol x(t) may berepresented as:

${x(t)} = {\sum\limits_{k}{{s_{k}(i)}{p_{T}\left( {t - T_{sym}} \right)}{\exp\left\lbrack {j\; 2\pi\;{f_{k}\left( {t - T_{sym} - \tau_{k}} \right)}} \right\rbrack}}}$

Where p_(T)(t) is a prototype filter function, T_(sym) is the start timeof the symbol period, τ_(k) is a subcarrier dependent time offset, andf_(k) is the frequency of subcarrier k. Prototype functions p_(T)(t) maybe, for example, rectangular time domain pulses, Gaussian time domainpulses or any other suitable function.

In some aspects, a sub-component of a transmitted signal consisting ofone subcarrier in the frequency domain and one symbol interval in thetime domain may be termed a resource element. Resource elements may bedepicted in a grid form. In some aspects, resource elements may begrouped into rectangular resource blocks consisting of 12 subcarriers inthe frequency domain and the P symbols in the time domain, where P maycorrespond to the number of symbols contained in one slot, and may be 6,7, or any other suitable number of symbols. In some alternative aspects,resource elements may be grouped into resource blocks consisting of 12subcarriers in the frequency domain and one symbol in the time domain.Each resource element 05 may be indexed as (k, 1) where k is the indexnumber of subcarrier, in the range 0 to N·M−1, where N is the number ofsubcarriers in a resource block, and M is the number of resource blocksspanning a component carrier in the frequency domain.

In some aspects, coding of the signal to be transmitted may include oneor more physical coding processes that may be used to provide coding fora physical channel that may encode data or control information. Codingmay also include multiplexing and interleaving that generates combinedcoded information by combining information from one or more sources,which may include one of more of data information and controlinformation, and which may have been encoded by one or more physicalcoding processes. The combined coded information may be input to ascrambler which may generate scrambled coded information. Physicalcoding process may include one or more of CRC attachment, code blocksegmentation, channel coding, rate matching and code blockconcatenation. An encoder that may be used to encode data according toone of a convolutional code and a tail-biting convolutional code.

A MAC entity that may be used to implement medium access control layerfunctions may include one or more of a controller, a logical channelprioritizing unit, a channel multiplexer & de-multiplexer, a PDU filterunit, random access protocol entity, data hybrid automatic repeatrequest protocol (HARQ) entity and broadcast HARQ entity. According tosome aspects, a higher layer may exchange control and status messageswith controller via management service access point. According to someaspects, MAC service data units (SDU) corresponding to one or morelogical channels may be exchanged with the MAC entity via one or moreservice access points (SAP). According to some aspects, a PHY SDUcorresponding to one or more transport channels may be exchanged with aphysical layer entity via one or more SAPs. According to some aspects,the logical channel prioritization unit may perform prioritizationamongst one or more logical channels, which may include storingparameters and state information corresponding to each of the one ormore logical channels, that may be initialized when a logical channel isestablished. According to some aspects, the logical channelprioritization unit may be configured with a set of parameters for eachof one or more logical channels, each set including parameters which mayinclude one or more of a prioritized bit rate (PBR) and a bucket sizeduration (BSD).

According to some aspects, the multiplexer & de-multiplexer may generateMAC PDUs, which may include one or more of MAC-SDUs or partial MAC-SDUscorresponding to one or more logical channels, a MAC header which mayinclude one or more MAC sub-headers, one or more MAC control elements,and padding data. According to some aspects, the multiplexer &de-multiplexer may separate one or more MAC-SDUs or partial MAC-SDUscontained in a received MAC PDU, corresponding to one or more logicalchannels, and may indicate the one or more MAC-SDUs or partial MAC-SDUsto a higher layer via one or more service access points. According tosome aspects, the HARQ entity and broadcast HARQ entity may include oneor more parallel HARQ processes, each of which may be associated with aHARQ identifier, and which may be one of a receive or transmit HARQprocess.

According to some aspects, a transmit HARQ process may generate atransport block (TB) to be encoded by the PHY according to a specifiedredundancy version (RV), by selecting a MAC-PDU for transmission.According to some aspects, a transmit HARQ process that is included in abroadcast HARQ entity may retransmit a same TB in successive transmitintervals a predetermined number of times. According to some aspects, atransmit HARQ process included in a HARQ entity may determine whether toretransmit a previously transmitted TB or to transmit a new TB at atransmit time based on whether a positive acknowledgement or a negativeacknowledgement was received for a previous transmission.

According to some aspects, a receive HARQ process may be provided withencoded data corresponding to one or more received TBs and which may beassociated with one or more of a new data indication (NDI) and aredundancy version (RV), and the receive HARQ process may determinewhether each such received encoded data block corresponds to aretransmission of a previously received TB or a not previously receivedTB. According to some aspects, a receive HARQ process may include abuffer, which may be implemented as a memory or other suitable storagedevice, and may be used to store data based on previously received datafor a TB. According to some aspects, a receive HARQ process may attemptto decode a TB, the decoding based on received data for the TB, andwhich may be additionally be based on the stored data based onpreviously received data for the TB.

FIG. 6 illustrates an architecture of a system of a network inaccordance with some embodiments. The system 600 is shown to include auser equipment (UE) 601 and a UE 602. The UEs 601 and 602 areillustrated as smartphones (e.g., handheld touchscreen mobile computingdevices connectable to one or more cellular networks), but may alsocomprise any mobile or non-mobile computing device, such as PersonalData Assistants (PDAs), pagers, laptop computers, desktop computers,wireless handsets, or any computing device including a wirelesscommunications interface.

In some embodiments, any of the UEs 601 and 602 can comprise an Internetof Things (IoT) UE, which can comprise a network access layer designedfor low-power IoT applications utilizing short-lived UE connections. AnIoT UE can utilize technologies such as machine-to-machine (M2M) or MTCfor exchanging data with an MTC server or device via a public landmobile network (PLMN), Proximity-Based Service (ProSe) ordevice-to-device (D2D) communication, sensor networks, or IoT networks.The M2M or MTC exchange of data may be a machine-initiated exchange ofdata. An IoT network describes interconnecting IoT UEs, which mayinclude uniquely identifiable embedded computing devices (within theInternet infrastructure), with short-lived connections. The IoT UEs mayexecute background applications (e.g., keep-alive messages, statusupdates, etc.) to facilitate the connections of the IoT network.

The UEs 601 and 602 may be configured to connect, e.g., communicativelycouple, with a radio access network (RAN) 610—the RAN 610 may be, forexample, an Evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), orsome other type of RAN. The UEs 601 and 602 utilize connections 603 and604, respectively, each of which comprises a physical communicationsinterface or layer (discussed in further detail below); in this example,the connections 603 and 604 are illustrated as an air interface toenable communicative coupling, and can be consistent with cellularcommunications protocols, such as a Global System for MobileCommunications (GSM) protocol, a code-division multiple access (CDMA)network protocol, a Push-to-Talk (PIT) protocol, a PTT over Cellular(POC) protocol, a Universal Mobile Telecommunications System (UMTS)protocol, a 3GPP Long Term Evolution (LTE) protocol, a 5G protocol, aNew Radio (NR) protocol, and the like.

In this embodiment, the UEs 601 and 602 may further directly exchangecommunication data via a ProSe interface 605. The ProSe interface 605may alternatively be referred to as a sidelink interface comprising oneor more logical channels, including but not limited to a PhysicalSidelink Control Channel (PSCCH), a Physical Sidelink Shared Channel(PSSCH), a Physical Sidelink Discovery Channel (PSDCH), and a PhysicalSidelink Broadcast Channel (PSBCH).

The UE 602 is shown to be configured to access an access point (AP) 606via connection 607. The connection 607 can comprise a local wirelessconnection, such as a connection consistent with any IEEE 802.11protocol, wherein the AP 606 would comprise a wireless fidelity (WiFi)router. In this example, the AP 606 is shown to be connected to theInternet without connecting to the core network of the wireless system(described in further detail below).

The RAN 610 can include one or more access nodes that enable theconnections 603 and 604. These access nodes (ANs) can be referred to asbase stations (BSs), NodeBs, evolved NodeBs (eNBs), next GenerationNodeBs (gNBs), RAN nodes, and so forth, and can comprise ground stations(e.g., terrestrial access points) or satellite stations providingcoverage within a geographic area (e.g., a cell). The RAN 610 mayinclude one or more RAN nodes for providing macrocells, e.g., macro RANnode 611, and one or more RAN nodes for providing femtocells orpicocells (e.g., cells having smaller coverage areas, smaller usercapacity, or higher bandwidth compared to macrocells), e.g., low power(LP) RAN node 612.

Any of the RAN nodes 611 and 612 can terminate the air interfaceprotocol and can be the first point of contact for the UEs 601 and 602.In some embodiments, any of the RAN nodes 611 and 612 can fulfillvarious logical functions for the RAN 610 including, but not limited to,radio network controller (RNC) functions such as radio bearermanagement, uplink and downlink dynamic radio resource management anddata packet scheduling, and mobility management.

In accordance with some embodiments, the UEs 601 and 602 can beconfigured to communicate using Orthogonal Frequency-DivisionMultiplexing (OFDM) communication signals with each other or with any ofthe RAN nodes 611 and 612 over a multicarrier communication channel inaccordance various communication techniques, such as, but not limitedto, an Orthogonal Frequency-Division Multiple Access (OFDMA)communication technique (e.g., for downlink communications) or a SingleCarrier Frequency Division Multiple Access (SC-FDMA) communicationtechnique (e.g., for uplink and ProSe or sidelink communications),although the scope of the embodiments is not limited in this respect.The OFDM signals can comprise a plurality of orthogonal subcarriers.

The physical downlink shared channel (PDSCH) may carry user data andhigher-layer signaling to the UEs 601 and 602. The physical downlinkcontrol channel (PDCCH) may carry information about the transport formatand resource allocations related to the PDSCH channel, among otherthings. It may also inform the UEs 601 and 602 about the transportformat, resource allocation, and H-ARQ (Hybrid Automatic Repeat Request)information related to the uplink shared channel. Typically, downlinkscheduling (assigning control and shared channel resource blocks to theUE 602 within a cell) may be performed at any of the RAN nodes 611 and612 based on channel quality information fed back from any of the UEs601 and 602. The downlink resource assignment information may be sent onthe PDCCH used for (e.g., assigned to) each of the UEs 601 and 602.

Some embodiments may use concepts for resource allocation for controlchannel information that are an extension of the above-describedconcepts. For example, some embodiments may utilize an enhanced physicaldownlink control channel (EPDCCH) that uses PDSCH resources for controlinformation transmission. The EPDCCH may be transmitted using one ormore enhanced the control channel elements (ECCEs). Similar to above,each ECCE may correspond to nine sets of four physical resource elementsknown as an enhanced resource element groups (EREGs). An ECCE may haveother numbers of EREGs in some situations.

The RAN 610 is shown to be communicatively coupled to a core network(CN) 620—via an S1 or NG interface 613. In embodiments, the CN 620 maybe an evolved packet core (EPC) network, a 5GC network, or some othertype of CN. In this embodiment, the S1 interface 613 is split into twoparts: the S1-U interface 614, which carries traffic data between theRAN nodes 611 and 612 and the serving gateway (S-GW) 622, and theS1-mobility management entity (MME) interface 615, which is a signalinginterface between the RAN nodes 611 and 612 and MMEs 621.

In this embodiment, the CN 620 comprises the MMEs 621, the S-GW 622, thePacket Data Network (PDN) Gateway (P-GW) 623, and a home subscriberserver (HSS) 624. The MMEs 621 may be similar in function to the controlplane of legacy Serving General Packet Radio Service (GPRS) SupportNodes (SGSN). The MMEs 621 may manage mobility aspects in access such asgateway selection and tracking area list management. The HSS 624 maycomprise a database for network users, including subscription-relatedinformation to support the network entities' handling of communicationsessions. The CN 620 may comprise one or several HSSs 624, depending onthe number of mobile subscribers, on the capacity of the equipment, onthe organization of the network, etc. For example, the HSS 624 canprovide support for routing/roaming, authentication, authorization,naming/addressing resolution, location dependencies, etc.

The S-GW 622 may terminate the S1 interface 613 towards the RAN 610, androutes data packets between the RAN 610 and the CN 620. In addition, theS-GW 622 may be a local mobility anchor point for inter-RAN nodehandovers and also may provide an anchor for inter-3GPP mobility. Otherresponsibilities may include lawful intercept, charging, and some policyenforcement.

The P-GW 623 may terminate an SGi interface toward a PDN. The P-GW 623may route data packets between the EPC network 623 and external networkssuch as a network including the application server 630 (alternativelyreferred to as application function (AF)) via an Internet Protocol (IP)interface 625. Generally, the application server 630 may be an elementoffering applications that use IP bearer resources with the core network(e.g., UMTS Packet Services (PS) domain, LTE PS data services, etc.). Inthis embodiment, the P-GW 623 is shown to be communicatively coupled toan application server 630 via an IP communications interface 625. Theapplication server 630 can also be configured to support one or morecommunication services (e.g., Voice-over-Internet Protocol (VoIP)sessions, PTT sessions, group communication sessions, social networkingservices, etc.) for the UEs 601 and 602 via the CN 620.

The P-GW 623 may further be a node for policy enforcement and chargingdata collection. Policy and Charging Rules Function (PCRF) 626 is thepolicy and charging control element of the CN 620. In a non-roamingscenario, there may be a single PCRF in the Home Public Land MobileNetwork (HPLMN) associated with a UE's Internet Protocol ConnectivityAccess Network (IP-CAN) session. In a roaming scenario with localbreakout of traffic, there may be two PCRFs associated with a UE'sIP-CAN session: a Home PCRF (H-PCRF) within a HPLMN and a Visited PCRF(V-PCRF) within a Visited Public Land Mobile Network (VPLMN). The PCRF626 may be communicatively coupled to the application server 630 via theP-GW 623. The application server 630 may signal the PCRF 626 to indicatea new service flow and select the appropriate Quality of Service (QoS)and charging parameters. The PCRF 626 may provision this rule into aPolicy and Charging Enforcement Function (PCEF) (not shown) with theappropriate traffic flow template (TFT) and QoS class of identifier(QCI), which commences the QoS and charging as specified by theapplication server 630.

The components of FIG. 6 are able to read instructions from amachine-readable or computer-readable medium (e.g., a non-transitorymachine-readable storage medium) and perform any one or more of themethodologies discussed herein. In particular, the processors (e.g., acentral processing unit (CPU), a reduced instruction set computing(RISC) processor, a complex instruction set computing (CISC) processor,a graphics processing unit (GPU), a digital signal processor (DSP) suchas a baseband processor, an application specific integrated circuit(ASIC), a radio-frequency integrated circuit (RFIC), another processor,or any suitable combination thereof) may read and follow theinstructions on a non-transitory medium.

Instructions may comprise software, a program, an application, anapplet, an app, or other executable code for causing at least any of theprocessors to perform any one or more of the methodologies discussedherein. The instructions may reside, completely or partially, within atleast one of the processors (e.g., within the processor's cache memory),the memory/storage devices, or any suitable combination thereof. In someembodiments, the instructions may reside on a tangible, non-volatilecommunication device readable medium, which may include a single mediumor multiple media. Furthermore, any portion of the instructions may betransferred to the hardware resources from any combination of theperipheral devices or the databases 606. Accordingly, the memory ofprocessors, the memory/storage devices, the peripheral devices, and thedatabases are examples of computer-readable and machine-readable media.

In the devices and systems above, a UE may send a service request to thenetwork to request the establishment of a NAS signalling connection andthe establishment of radio and/or S1 bearers. The service request may besent by the UE for a variety of reasons, which may include when the UEis in the EMM-Idle mode and receives a paging request with a corenetwork domain indicator set to “PS” (Public Safety) from the network,or when the UE has user data or uplink control signaling to be sent. Thenetwork may reject the service request; alternatively, the MME mayinitiate EMM common procedures e.g. authentication and security modecontrol procedures.

When attempting a service request for a non-emergency IMS call (alsocalled multimedia telephony service (MMTEL) call) transmitted from theUE to the network, a timer may be used to determine when to abort theservice request procedure. The service request timer, timer T3417, mayhave a default value of 5 s and be used when the UE is in theEMM-SERVICEREQUEST INITIATED state. Timer T3417 normally stops when thebearers have been set up or the service request has been received andotherwise, the service request procedure aborted. The lack of responsefrom the network may be due, among others, to channel conditions or afailure within the EPC.

The service request procedure may initiate a change of the EMM mode ofthe UE from EMM-IDLE to EMM-CONNECTED mode. The service requestprocedure may be used by the UE in EMM-IDLE mode to establish radio andS1 bearers when user data or signalling is to be sent by the UE or bythe UE in EMM-IDLE or EMM-CONNECTED mode to invoke mobile originating(MO)/(MT) terminating CS fallback or 1×CS fallback.

The UE may attempt the service request procedure multiple times. Aservice request attempt counter may be used to avoid situations wherethe UE is stuck in a loop, attempting the service request when timerT3417 expires. This may occur, as above, when the UE does not receive arejection from the MME, nor receive a radio bearer establishmentindication from the access stratum. If the service request attemptcounter is greater than or equal to 5, the UE may start timer T3325. Thedefault value of timer T3325 is 60 Sec. While timer T3325 is inoperation, no service request is permitted to be initiated by the UE.

The current 3GPP specification does not differentiate between anon-emergency IP Multimedia Subsystem (IMS) call and normal PS data. Thelatter of which may include SMS messages, web browsing and email, amongothers, for which users may be less sensitive compared with IMS calls.The operation of running of T3325 timer may result in mobile-originatedIMS calls being blocked as the service request procedure is not allowed.

Some UE may be able to operate using different Radio Access Technologies(RATs). Such a multimode UE may have multiple options to make voicecalls—like circuit-switched (CS) fallback, voice calls over the CSdomain, voice over other IP Connectivity Access Network (IP-CAN) etc.However, the current 3GPP specification has not taken multimodeoperation into consideration to recover from the above issues in LTE RATand to make a successful voice call by other means. Thus, during theservice request procedure attempts, the UE is stuck retrying the IMScall on the EUTRAN without trying the CS-Domain or other IP-CANsavailable. Furthermore, once the service request attempt counter reachesthe maximum number of attempts (e.g., 5-5 service requests to thenetwork resulting in no response), the UE is not allowed to initiate theservice request procedure for a duration of the T3325 timer (whosedefault value is 60 sec) after the last retry. In this case, if the userattempts to initiate an IMS call when timer T3325 is running, the UE isnot allowed to initiate the service request procedure for establishingIMS bearer services, and eventually the call will fail. The servicerequest attempt counter may increment independent of whether the SRattempts are caused by a non-emergency IMS call or PS data.

IMS emergency calls may avoid this problem by being a high priority andeliminating incrementing of the service request attempt counter for IMSemergency calls. In this case, when service requests are blocked due tothe maximum failure attempt being reached and timer T3325 is running, aservice request for an IMS emergency call may avoid being blocked. This,however, may not apply for non-emergency IMS voice calls.

To overcome the above issues, in some embodiments, non-emergency IMScalls may be treated differently from PS data service. This may betreated as an abnormal case as given in 3GPP TS 24.301, section 5.6.1.6.FIG. 7 illustrates a service request procedure in accordance with someembodiments. In particular, as shown in FIG. 7 , before the servicerequest 708 to the network 704 is blocked due to the service requestattempt counter having reached the maximum value (e.g. 5) (i.e., T3325is not running), the UE 702 may be allowed to perform the servicerequest procedure for a non-emergency IMS call 706 for a configurablemaximum number ‘n’ of attempts (e.g. with ‘n’ configurable in the range1 to 5). After the ‘n’th T3417 timer expiry, the UE 702 may indicate IMScall failure to the upper layers of the UE 702. The service requestprocedure may include the UE encoding a service request for transmissionto the network, where, when received the service request is decoded andthe network takes the appropriate action.

This can be extended to encompass the case in which T3325 is running.FIG. 8 illustrates a service request procedure in accordance with someembodiments. In particular, as shown in FIG. 8 , even when the servicerequest 808 to the network 804 is blocked due to the service requestattempt counter having reached the maximum value (e.g. 5-5 servicerequests 808 to the network 804 resulting in no response) and T3325 isrunning, the UE 802 may be allowed to perform the service requestprocedure for a non-emergency IMS call 806 for a configurable maximumnumber ‘m’ of attempts (e.g. with ‘m’ configurable in the range 0 to 5).After the ‘m’th T3417 timer expiry, the UE 802 may indicate IMS callfailure to the upper layers.

The indication to the upper layers may result in trying the call on theCS domain, if not already attempted or any other available IP-CAN. Thedomains may be prioritized so that if multiple domains are available,the domain used may be selected using the prioritization. The values mand n may be different and, in some embodiments, may not be configurableby the UE or network (i.e., set by the 3GPP standards). The indicationmay result in the UE trying the IMS call on CS domain or any otheravailable IP-CAN, if not already attempted.

FIG. 9 illustrates a service request procedure in accordance with someembodiments. As shown, multiple service requests 906 may be transmittedfrom the UE 902 to the network 904. In some embodiments, if the servicerequest attempt counter has reached the maximum value (e.g. 5) due to aservice request procedure failure, after starting timer T3325, the UE902 can disable the E-UTRA capability for the T3325 duration (as per3GPP TS 24.301 Section 4.5). The UE 902 store in memory the identity ofthe PLMN where the E-UTRA capability was disabled and use the storedinformation in subsequent PLMN selections as specified in 3GPP TS23.122. While the timer T3325 is running and an IMS call is initiated,the UE 902 may also try the IMS call on another RAT. The available RATsmay be stored in the UE memory and attempts made based on RATprioritizations also stored in the UE memory. The prioritizations may bebased, for example, on UE characteristics or RAT traffic.

FIG. 10 illustrates a flowchart of a service request procedure inaccordance with some embodiments. The operations of the flowchart 1000may be undertaken by the UE shown and described above and may haveadditional operations or fewer operations than that shown. For example,operations that show the UE attempting to find a cell on anothersupported RAT (CS domain or other available IP-CAN) after the T3325timer is started, and, if found, disabling the E-UTRA capability for theT3325 timer duration for the current PLMN so that if there is an IMScall, the other domain may be used are not provided in FIG. 10 . Suchoperations may be added after operation 1020, for example.

As shown in FIG. 10 , the UE may be configured at operation 1002 withone or both of the maximum number of service request attempts (dependenton whether timer T3325 is running) for an IMS call. In some embodiments,either or both the maximum number of attempts may be configured multiplemaximum number of attempts, the maximum number of attempts used may bedependent on the UE or user (e.g., user priority, for example if theuser is an emergency service provider) and/or the circumstances of theservice request not being fulfilled (e.g., no response from the network,network congestion, network failure). The number of service attempts maybe, in some examples, 1-5. In some embodiments, a managed object (MO)may be used to introduce the counter values. This value may be used ifnot updated. In other embodiments, the maximum number of attempts maynot be configurable but may be set to a predetermined number dependenton the standard (as above, 5).

In FIG. 10 , the IMS call may be given higher priority than PS dataduring the service request procedure. Thus, the UE may at operation 1004determine that an IMS call is to be placed and perform a differentprocedure than if the service request is to be for a PS datatransmission.

When the UE determines that an IMS call is to be placed, the UE maydetermine at operation 1006 whether the T3325 timer is running. In otherwords, the UE may determine whether service requests for a previous IMScall or PS data transmission has caused the T3417 counter to exceed themaximum value. Although not shown, the T3417 counter may be reset priorto initiation of the T3325 timer, such as after the maximum count hasbeen reached, after transmission of the data or after transmission ofthe failure indication described below.

If the T3325 timer is running, the UE may determine at operation 1010whether the T3417 counter has exceeded a first (configured) counter(maximum number of service requests) when the T3325 timer is running.Similarly, if the T3325 timer is not running, the UE may determine atoperation 1008 whether the T3417 counter has exceeded a second(configured) counter when the T3325 timer is not running. As above, insome embodiments the first and second maximum number of service requestsmay be independent—e.g., they may be different. Alternatively, the firstand second counter may be the same, e.g., 5, as determined by thestandard.

Whether or not the T3325 timer is running, if the first or secondcounter (dependent on whether or not the T3325 timer is running) hasbeen met, the failure may be indicated to the upper layers. In someembodiments, this may result in the UE determining which IP-CANs areavailable and which IP-CANs the UE has already attempted to use for theIMS call. For example, the UE may try the IMS call on the CS domain ifnot already attempted. This may involve the UE registering on the otherRAT, among other procedures.

Dependent on whether or not the T3325 timer is running, if the first orsecond counter has not been met, the UE may at operation 1012 transmitthe service request to the network. Thus, in some situations, even whenservice request is blocked due to the service request attempt counterhaving reached the value of 5 and the T3325 timer running, the UE may bepermitted to perform the service request procedure for a non-emergencyIMS call.

After transmission of the service request, the UE may wait for aresponse from the network. Similar to the above, the UE may activate theT3417 timer to determine whether or not a response has been received. Ifa response has not been received by the time the T3417 timer expires,the UE may at operation 1016 increment the first or second counter(again, dependent on whether or not the T3325 timer is running) and thenreturn to operation 1008. If, on the other hand, the network respondswith an uplink grant (indicating that the appropriate bearers have beenestablished), at operation 1018 the UE may transmit the data on theuplink grant.

As above, 3GPP TS 24.301, subclause 5.6.1.6 may be adjusted for theabnormal case of the T3417 timer having expired. As above, the UE mayenter the EMM-REGISTERED state. If the UE triggered the service requestprocedure in EMM-IDLE mode to obtain packet services, then the EMMsublayer may increment the service request attempt counter, abort theprocedure and release locally any resources allocated for the servicerequest procedure. If the service request attempt counter is greaterthan or equal to 5, the UE may start timer T3325. Additionally, if theservice request is initiated for a mobile originated MMTEL voice callthen the UE may inform the upper layers of the failure to establish theconnection. This can result in the upper layers requesting establishmentof a voice call (if not already attempted in the CS domain), or otherimplementation-specific mechanisms can result in the MMTEL call beingattempted using another IP-CAN. The UE may not attempt a service requestuntil expiry of timer T3325 unless the UE is registered in a new PLMN.

In some embodiments, this procedure can be generalized to a multimode UEinitially attempting to access the network via a first RAT (above theLTE network, but in other embodiments, another IP-CAN). The first RATmay offer both voice and data services. The UE may wait for a responsefrom the network. If the UE does not receive a response from the networkwithin a time interval T1, the UE may subsequently re-attempt the accessto the network via the first RAT. The UE may continue to re-attemptnetwork access via the first RAT a predetermined number of times. Oncethe predetermined number of re-attempts has occurred (due tonon-responses from the network), the UE may refrain during a timeinterval T2 from further access attempts for a first purpose (or thatare not for a second purpose) via the first RAT. Thus, for example, theUE may refrain from further access attempts for a first purpose of dataservices or may permit further access attempts for a second purpose ofvoice services during the time interval T2. While in some embodiments,the UE may refrain during the time interval T2 from further accessattempts via the first RAT for any purpose, the UE may permit accessattempts via a second RAT for the second purpose (e.g., voice services)during the time interval T2 (but not for the first purpose). In thiscase, the UE may disable the first RAT during the time interval T2. Insome situations, the UE may thus move transmission of service requestsfor, say voice services, after a threshold number of service requestattempts from the first RAT to the second RAT (where if the thresholdnumber is 0, the transmission is moved immediately or directly from thefirst RAT to the second RAT). The UE may be limited to a single secondRAT during the time interval T2 or may try to access the network viamultiple RATs in a previously prioritized order. The number of attemptsmade using each RAT may be the same, or may be independent of each otherand may be dependent on the type of RAT used.

In some embodiments, the first RAT may be Evolved Universal MobileTelecommunications System Terrestrial Radio Access Network (E-UTRAN) andthe second RAT may be a Global System for Mobile communication(GSM)/Edge Radio Access Network (GERAN) or UTRAN supporting voiceservices via circuit-switched (CS) domain or an Internet Protocol(IP)-Connectivity Access Network (IP-CAN) for an IP Multimedia Subsystem(IMS) supporting voice services. The IP-CAN may be a wireless local areanetwork (WLAN) or a General Packet Radio System (GPRS).

Thus, different embodiments may indicate changes when the servicerequest attempt occurs while T3325 time is not running, and T3325 timeris started due to this failure and when a new service request attemptoccurs while T3325 is already running. In the latter embodiment with theparameter ‘m’=0 (if new service request attempt occurs while T3325 isalready running), the notification may be provided to the upper layersimmediately, without trying to send the service request. In the latterembodiment with the parameter ‘m’=1, the UE may be permitted to send theservice request once while T3325 is already running. If the T3417 timerthen expires, the notification may be provided to the upper layers.

Examples

Example 1 is an apparatus of a user equipment (UE), the apparatuscomprising: processing circuitry arranged to: determine whether userdata to be transmitted to a network is non-emergency user data oremergency user data; if a T3325 timer is not running: initiatetransmission of a service request to the network and initiate a T3417timer; increment a service request attempt counter if a response to theservice request has not been received from the network before expirationof the T3417 timer and if the user data is non-emergency user data; andinitiate the T3325 timer if the service request attempt counter at leastmeets a predetermined value; and if the T3325 timer is running: if theservice request is initiated for a multimedia telephony (MMTEL) call,attempt to establish the MMTEL call on an alternative radio accessnetwork; and a memory arranged to store the predetermined value.

In Example 2, the subject matter of Example 1 includes, wherein theprocessing circuitry is further arranged to: attempt to establish theMMTEL call as a circuit switched (CS) voice call if not alreadyattempted in a CS domain.

In Example 3, the subject matter of Example 2 includes, timer isrunning: notify upper layers that the service request was not accepted,wherein notification is dependent on whether the service request isinitiated for the MMTEL call; and receive a request from the upperlayers to establish the CS voice call if the CS voice call is notalready attempted in a CS domain.

In Example 4, the subject matter of Example 3 includes, wherein theprocessing circuitry is further arranged to: provide the notification ifthe service request attempt counter at least meets the predeterminedvalue.

In Example 5, the subject matter of Example 4 includes, wherein: thepredetermined value is 5.

In Example 6, the subject matter of Examples 1-5 includes, wherein theprocessing circuitry is further arranged to: increment the servicerequest attempt counter if the UE is in EMM-Idle mode and a servicerequest procedure is triggered.

In Example 7, the subject matter of Example 6 includes, wherein theprocessing circuitry is further arranged to: abort the service requestprocedure and release locally any resources allocated for the servicerequest procedure in response to expiration of the T3417 timer.

In Example 8, the subject matter of Examples 1-7 includes, wherein theprocessing circuitry is further arranged to: refrain from incrementingthe service request attempt counter for emergency user data.

In Example 9, the subject matter of Examples 1-8 includes, wherein theprocessing circuitry is further arranged to: use a different radioaccess technology (RAT) for the MMTEL call if the T3325 timer is runningthan if the T3325 timer is not running.

In Example 10, the subject matter of Example 9 includes, wherein theprocessing circuitry is further arranged to: use Long Term Evolution(LTE) if the T3325 timer is not running, regardless of whether theservice request is for the MMTEL call, and use CS fallback for a nonemergency voice call over the CS domain if the T3325 timer is running.

In Example 11, the subject matter of Examples 9-10 includes, wherein theprocessing circuitry is further arranged to: prioritize a plurality ofRATs; and use, to transmit the service request over a highest priorityRAT for which the service request attempt counter has not reached apredetermined value, if the T3325 timer is running.

In Example 12, the subject matter of Examples 1-11 includes, wherein theprocessing circuitry is further arranged to: treat a non-emergency voicecall and data differently if the T3325 timer is running, at least oneservice request for the non-emergency voice call transmitted if theT3325 timer is running and service requests for the data being preventedfrom being transmitted over a same radio access technology (RAT) if theT3325 timer is running.

In Example 13, the subject matter of Examples 1-12 includes, wherein:the predetermined value of the service request attempt counter if theT3325 timer is running is independent of the predetermined value of theservice request attempt counter if the T3325 timer is not running.

In Example 14, the subject matter of Examples 1-13 includes, wherein:the predetermined value of the service request attempt counter if theT3325 timer is running is the same as the predetermined value of theservice request attempt counter if the T3325 timer is not running.

In Example 15, the subject matter of Examples 1-14 includes, wherein theprocessing circuitry is further arranged to: prevent, if the T3325 timeris running, service requests from being transmitted on a Radio AccessTechnology (RAT) that is used if the T3325 timer is not running.

In Example 16, the subject matter of Examples 1-15 includes, wherein:the processing circuitry comprises a baseband processor configured toencode transmissions to, and decode transmissions from, the network.

Example 17 is an apparatus of a user equipment (UE), the apparatuscomprising: processing circuitry arranged to: initiate repeatedoperations that comprise the processing circuitry being arranged to:encode a service request for transmission to a network via a first radioaccess technology (RAT); determine whether a response to the servicerequest has been received from the network within a first time period;in response to a determination that the response has not been receivedwithin the first time period, increment a counter; and afterincrementation of the counter, determine whether the counter has atleast reached a predetermined value; in response to a determination thatthe counter is less than the predetermined value, return to the repeatedoperations; and in response to a determination that the counter has atleast reached the predetermined value, refrain from further transmissionof service requests for data services and initiate further transmissionof service requests for non-emergency voice services.

In Example 18, the subject matter of Example 17 includes, wherein theprocessing circuitry is further arranged to: initiate furthertransmission of service requests for non-emergency voice services duringa second time period via a second RAT.

In Example 19, the subject matter of Example 18 includes, wherein theprocessing circuitry is further arranged to: refrain from transmissionof service requests for non-emergency voice services during the secondtime period via the first RAT, if a number of transmissions via thefirst RAT for which the UE did not receive a response from the networkwithin the first time period is at least a threshold value.

In Example 20, the subject matter of Example 19 includes, wherein: thethreshold value is zero, transmissions of the service requests are movedimmediately from the first RAT to the second RAT.

In Example 21, the subject matter of Examples 18-20 includes, whereinthe processing circuitry is further arranged to: refrain fromtransmission of service requests for non-emergency voice servicesoutside of the second time period via the first RAT, if a number oftransmissions via the first RAT for which the UE did not receive aresponse from the network within the first time period is at leastanother threshold value.

In Example 22, the subject matter of Examples 17-21 includes, whereinthe processing circuitry is further arranged to: initiate furthertransmission of service requests for non-emergency voice services duringa second time period via the first RAT.

In Example 23, the subject matter of Examples 17-22 includes, wherein:the first RAT is an Evolved Universal Mobile Telecommunications SystemTerrestrial Radio Access Network (E-UTRAN) and the second RAT is aGlobal System for Mobile communication (GSM)/Edge Radio Access Network(GERAN) or UTRAN supporting voice services via circuit-switched (CS)domain or an Internet Protocol (IP)-Connectivity Access Network (IP-CAN)for an IP Multimedia Subsystem (IMS) supporting voice services.

In Example 24, the subject matter of Example 23 includes, wherein: theIP-CAN is a wireless local area network (WLAN) or a General Packet RadioSystem (GPRS).

In Example 25, the subject matter of Examples 23-24 includes, whereinthe processing circuitry is further arranged to: in response to adetermination that the counter has at least reached the predeterminedvalue, attempt to select a second RAT that supports voice services froma plurality of RATs; and in response to finding the second RAT, disableoperation of the UE in the first RAT for a time period T3.

Example 26 is a computer-readable storage medium that storesinstructions for execution by one or more processors of a user equipment(UE), the one or more processors to configure the UE to, if theinstructions are executed: receive a request to transmit a user data toa network; determine whether a T3325 timer is running, the T3325 timerinitiated if a service request attempt counter at least meets apredetermined value; increment the service request attempt counter eachtime a response to a service request to a network has not been receivedfrom the network before expiration of a T3417 timer; and transmit aservice request to the network if the T3325 timer is running and theservice request is for a non-emergency multimedia telephony (MMTEL)voice call and refrain from transmission of the service request if theT3325 timer is running and the service request is for non-emergency datathat is not the MMTEL call.

In Example 27, the subject matter of Example 26 includes, wherein theinstructions, when executed, further configure the UE to: transmit theservice request on a different radio access technology (RAT) dependenton whether the T3325 timer is running, and use Long Term Evolution (LTE)if the T3325 timer is not running and use circuit-switched (CS) fallbackif the T3325 timer is running.

In Example 28, the subject matter of Examples 26-27 includes, whereinthe instructions, when executed, further configure the UE to: prioritizea plurality of RATs; and use, to transmit the service request if theT3325 timer is running, a highest priority RAT for which the servicerequest attempt counter has not reached a predetermined value.

In Example 29, the subject matter of Examples 26-28 includes, whereinthe instructions, when executed, further configure the UE to: determinethat the service request attempt counter at least meets thepredetermined value and inform upper layers that the service requestattempt counter at least meets the predetermined value and subsequentlyuse a different RAT to transmit the service request to the network.

In Example 30, the subject matter of Examples 26-29 includes, whereinthe instructions, when executed, further configure the UE to: prevent,if the T3325 timer is running, service requests from being transmittedon a RAT used if the T3325 timer is not running.

Example 31 is an apparatus of a user equipment (UE), the apparatuscomprising: means for determining whether user data to be transmitted toa network is non-emergency user data or emergency user data; if a T3325timer is not running: means for initiating transmission of a servicerequest to the network and initiate a T3417 timer; means forincrementing a service request attempt counter if a response to theservice request has not been received from the network before expirationof the T3417 timer and if the user data is non-emergency user data; andmeans for initiating the T3325 timer if the service request attemptcounter at least meets a predetermined value; and if the T3325 timer isrunning: if the service request is initiated for a multimedia telephony(MMTEL) call, means for attempting to establish the MMTEL call on analternative radio access network.

In Example 32, the subject matter of Example 31 includes, means forattempting to establish the MMTEL call as a circuit switched (CS) voicecall if not already attempted in a CS domain.

In Example 33, the subject matter of Example 32 includes, timer isrunning: means for notifying upper layers that the service request wasnot accepted, wherein notification is dependent on whether the servicerequest is initiated for the MMTEL call; and means for receiving arequest from the upper layers to establish the CS voice call if the CSvoice call is not already attempted in a CS domain.

In Example 34, the subject matter of Example 33 includes, means forproviding the notification if the service request attempt counter atleast meets the predetermined value.

In Example 35, the subject matter of Example 34 includes, wherein: thepredetermined value is 5.

In Example 36, the subject matter of Examples 31-35 includes, means forincrementing the service request counter if the UE is in EMM-Idle modeand a service request procedure is triggered.

In Example 37, the subject matter of Example 36 includes, means foraborting the service request procedure and release locally any resourcesallocated for the service request procedure in response to expiration ofthe T3417 timer.

In Example 38, the subject matter of Examples 31-37 includes, means forrefraining from incrementing the service request attempt counter foremergency user data.

In Example 39, the subject matter of Examples 31-38 includes, means forusing a different radio access technology (RAT) for the MMTEL call ifthe T3325 timer is running than if the T3325 timer is not running.

In Example 40, the subject matter of Example 39 includes, means forusing Long Term Evolution (LTE) if the T3325 timer is not running,regardless of whether the service request is for the MMTEL call, and useCS fallback for a non emergency voice call over the CS domain if theT3325 timer is running.

In Example 41, the subject matter of Examples 39-40 includes, means forprioritizing a plurality of RATs; and means for using, to transmit theservice request if the T3325 timer is running, a highest priority RATfor which the service request attempt counter has not reached apredetermined value.

In Example 42, the subject matter of Examples 39-41 includes, means fortransmitting the service request to the network via the RAT.

In Example 43, the subject matter of Examples 31-42 includes, means fortreating a non-emergency voice call and data differently if the T3325timer is running, at least one service request for the non-emergencyvoice call transmitted if the T3325 timer is running and servicerequests for the data being prevented from being transmitted over a sameradio access technology (RAT) if the T3325 timer is running.

In Example 44, the subject matter of Examples 31-43 includes, wherein:the predetermined value of the service request attempt counter if theT3325 timer is running is independent of the predetermined value of theservice request attempt counter if the T3325 timer is not running.

In Example 45, the subject matter of Examples 31-44 includes, wherein:the predetermined value of the service request attempt counter if theT3325 timer is running is the same as the predetermined value of theservice request attempt counter if the T3325 timer is not running.

In Example 46, the subject matter of Examples 31-45 includes, means forpreventing, if the T3325 timer is running, service requests from beingtransmitted on a Radio Access Technology (RAT) that is used if the T3325timer is not running.

Example 47 is at least one machine-readable medium includinginstructions that, when executed by processing circuitry, cause theprocessing circuitry to perform operations to implement of any ofExamples 1-46.

Example 48 is an apparatus comprising means to implement of any ofExamples 1-46.

Example 49 is a system to implement of any of Examples 1-46.

Example 50 is a method to implement of any of Examples 1-46.

Although an embodiment has been described with reference to specificexample embodiments, it will be evident that various modifications andchanges may be made to these embodiments without departing from thebroader scope of the present disclosure. Accordingly, the specificationand drawings are to be regarded in an illustrative rather than arestrictive sense. The accompanying drawings that form a part hereofshow, by way of illustration, and not of limitation, specificembodiments in which the subject matter may be practiced. Theembodiments illustrated are described in sufficient detail to enablethose skilled in the art to practice the teachings disclosed herein.Other embodiments may be utilized and derived therefrom, such thatstructural and logical substitutions and changes may be made withoutdeparting from the scope of this disclosure. This Detailed Description,therefore, is not to be taken in a limiting sense, and the scope ofvarious embodiments is defined only by the appended claims, along withthe full range of equivalents to which such claims are entitled.

The Abstract of the Disclosure is provided to comply with 37 C.F.R.1.72(b), requiring an abstract that will allow the reader to quicklyascertain the nature of the technical disclosure. It is submitted withthe understanding that it will not be used to interpret or limit thescope or meaning of the claims. In addition, in the foregoing DetailedDescription, it can be seen that various features are grouped togetherin a single embodiment for the purpose of streamlining the disclosure.This method of disclosure is not to be interpreted as reflecting anintention that the claimed embodiments require more features than areexpressly recited in each claim. Rather, as the following claimsreflect, inventive subject matter lies in less than all features of asingle disclosed embodiment. Thus, the following claims are herebyincorporated into the Detailed Description, with each claim standing onits own as a separate embodiment.

What is claimed is:
 1. An apparatus of a user equipment (UE), theapparatus comprising: processing circuitry arranged to, for a servicerequest procedure that includes initiation of a service request: when aT3325 timer is not running: initiate transmission of the service requestto a network and initiate a T3417 timer; increment a service requestattempt counter when a response to the service request has not beenreceived from the network before expiration of the T3417 timer and userdata is non-emergency user data; and initiate the T3325 timer when theservice request attempt counter at least meets a predetermined value;and when the T3325 timer is running and the service request wasinitiated for a non-emergency multimedia telephony (MMTEL) call: notifyupper layers that the service request was not accepted, and receive arequest from the upper layers to establish a circuit switched (CS) voicecall when not already attempted in a CS domain; and a memory arranged tostore the predetermined value.
 2. The apparatus of claim 1, wherein theprocessing circuitry is further arranged to: provide a notification whenthe service request attempt counter at least meets the predeterminedvalue.
 3. The apparatus of claim 2, wherein: the predetermined value is5.
 4. The apparatus of claim 1, wherein the processing circuitry isfurther arranged to: increment the service request attempt counter whenthe UE is in EMM-Idle mode and a service request procedure is triggered.5. The apparatus of claim 4, wherein the processing circuitry is furtherarranged to: abort the service request procedure and release locally anyresources allocated for the service request procedure in response toexpiration of the T3417 timer.
 6. The apparatus of claim 1, wherein theprocessing circuitry is further arranged to: refrain from incrementingthe service request attempt counter for emergency user data.
 7. Theapparatus of claim 1, wherein the processing circuitry is furtherarranged to: use a different radio access technology (RAT) for the MMTELcall when the T3325 timer is running than when the T3325 timer is notrunning.
 8. The apparatus of claim 7, wherein the processing circuitryis further arranged to: use Long Term Evolution (LTE) when the T3325timer is not running, regardless of whether the service request is forthe MMTEL call, and use CS fallback for a non emergency voice call overthe CS domain when the T3325 timer is running.
 9. The apparatus of claim7, wherein the processing circuitry is further arranged to: prioritize aplurality of RATs; and use, to transmit the service request over ahighest priority RAT for which the service request attempt counter hasnot reached a predetermined value, when the T3325 timer is running. 10.The apparatus of claim 1, wherein the processing circuitry is furtherarranged to: treat a non-emergency voice call and data differently whenthe T3325 timer is running, at least one service request for thenon-emergency voice call transmitted when the T3325 timer is running andservice requests for the data being prevented from being transmittedover a same radio access technology (RAT) when the T3325 timer isrunning.
 11. The apparatus of claim 1, wherein: the predetermined valueof the service request attempt counter when the T3325 timer is runningis independent of the predetermined value of the service request attemptcounter when the T3325 timer is not running.
 12. The apparatus of claim1, wherein: the predetermined value of the service request attemptcounter when the T3325 timer is running is the same as the predeterminedvalue of the service request attempt counter when the T3325 timer is notrunning.
 13. The apparatus of claim 1, wherein the processing circuitryis further arranged to: prevent, when the T3325 timer is running,service requests from being transmitted on a Radio Access Technology(RAT) that is used when the T3325 timer is not running.
 14. Theapparatus of claim 1, wherein: the processing circuitry comprises abaseband processor configured to encode transmissions to, and decodetransmissions from, the network.